BOSTON _ They are not nominating a president of black America at the Democratic National Convention. But in coming years, this week in Boston may be seen as a signal moment in the changing of the guard of the nation’s black political leadership.

It is the last act of the Rev. Al Sharpton’s failed bid to grab the mantle long held by the Rev. Jesse Jackson, and the debut star turn of Barack Obama, the state senator from Chicago who is the odds-on favorite to become only the third black in the U.S. Senate since Reconstruction _ and someone already being talked about for a future national ticket.

“I think this is really the end of an era of race and politics,” said Angela Dillard, a history professor at New York University whose specialty is race and politics. “Something’s shifting and changing and people like Sharpton can’t change with it, and something new and different is being created and it is about people like Obama.”

The old model of the black protest leader making demands no longer makes sense in an age tapped out and tired of race, Dillard said. But Obama can argue for policies virtually indistinguishable from Sharpton’s in cooler, non-racial terms, while still affirming a message of racial identity and uplift implicit in his very being.

“I think he is talking about race when he’s not,” Dillard said. “Something about the way he pitches things is perfect for this moment.”

Both Obama and Sharpton were given speaking roles at the tightly scripted convention. Obama was awarded the plum role of keynote speaker Tuesday night, while Sharpton got eight minutes Wednesday.

Sharpton and Obama could not be more different in style and biography. Obama, the son of a white mother and Kenyan father he barely knew, was the first black president of the Harvard Law Review. Sharpton, who counts James Brown the closest thing to a father figure, was an ordained preacher while still a small child. Sharpton practices the politics of controversy and polarization. Obama listens, reasons and calms.

For the Democrats, said Jeremy Mayer, a political scientist at George Mason University, “Obama is a godsend.”

In the context of modern Democratic Party and black politics, both emerge from the receding shadow of Jesse Jackson, who in two remarkable candidacies for the presidency in 1984 and 1988 established himself as the preeminent black politcal figure in America.

This year, for the first time since 1984, Jackson will not address the convention. But if he is no longer playing a commanding role, it is not at all clear that the role still exists, and plain that if it does, black voters were not prepared to hand the portfolio to Sharpton.

“I don’t think black America chose him to lead,” said Mayer, who wrote the book, “Running on Race.”

“What we are seeing here is the maturing of the black vote,” Mayer said.

In 1988, Jackson won 13 primaries and caucuses and placed second in 33. This year Sharpton won nowhere, accumulating 27 delegates, enough to fill two elevators at the Park Plaza Hotel, where they came to huddle with their candidate, a rare encounter in a campaign that was often little more than a string of Sharpton TV appearances.

“I don’t believe (the Sharpton campaign) had that much of an impact on what’s going on here,” said Gerald Rowe, a Sharpton delegate from Detroit, where he is the political director of his United Auto Workers local.

Rowe signed on with Sharpton because he liked the attention he drew to issues of importance to the inner city. “He’s a good speaker, a good presenter,” Rowe said.

But he does not see Sharpton as truly a national figure. “He’s another individual,” Rowe said. “I don’t think we need a new Jesse Jackson.”

For Ronald Walters, an authority on black politics at the University of Maryland who advised Jackson in both presidential campaigns, Jackson was vexed by the assumption that he was not running as a “real” candidate. In Jackson’s own mind, Walters said, he was always running to win.

But, Walters believes, the next black candidate for president will be “a different kind of black candidate who runs seriously and is perceived to be running seriously for president.”

Enter Obama, who may be the first candidate to generate so much talk about his national prospects while still a state legislator.

This week, the conservative National Review Online predicted that if Obama becomes the only black in the Senate, he could find himself on the 2012 ticket,“and maybe not even the bottom of the ticket.”

Earlier, Noam Scheiber, writing in The New Republic, concluded that “were Obama to win in November, he would instantly become the de facto political leader of the country’s African-American community” and “a perennial possibility for a spot on a national Democratic ticket.”

While Obama has done nothing to invite such speculation, aside from succeeding, the notion that he would be black America’s leader may prove even more burdensome than the expectation that he might someday seek the presidency.

Danny Davis, a Chicago congressman who was an early Obama backer, said black candidates seeking higher office are always on the knife’s edge of either appearing to whites to be “too strong on black-oriented issues” or, conversely, not strong enough for the black base.

But, Davis said, “it seems like Barack has this quality about him that makes people go for him,” managing to win the hearts and minds of white voters in suburban and small-town Illinois while staying good “in the hood.”

“Barack is not going to be viewed as a Frederick Douglass, he’s not going to be a Jesse Jackson, but he doesn’t have to be, and he will not run away from black issues,” Davis said.

On the convention floor, Emil Jones Jr., president of the Illinois Senate, who has mentored Obama since he was a young community activist, beamed up at the podium where Obama would be introduced to a national audience.